As a central tenet of this model is the conceptualization that use behavior motivated by different needs constitutes phenomenologically distinct behaviors, and that these distinct use behaviors may be differently associated with mental health outcomes. Data will come from the Cannabis, Health and Young Adult Study , with a sample size of 366 comprised of young adults, in Los Angeles, who use marijuana for recreational and/or medical reasons. The first aim focuses on confirming and validating the instrument used to operationalize motives of marijuana use in young adults who use marijuana for recreational and/or medical reasons and to evaluate whether this factor structure varies by gender. The second aim investigates the associations between motives of marijuana use and symptoms of depression, symptoms of anxiety, and overall psychological distress for young adults in the CHAYA study. The third aim examines whether the associations between motives of marijuana use and symptoms of depression, symptoms of anxiety, and overall psychological distress differ by gender in this sample. The Literature Review is presented in chapter 2, followed by Methods in chapter 3. Chapters 4 and 5 cover the Results and Discussion, respectively. Finally, a Conclusion and Future Directions are presented in chapter 6. Young adulthood. Emerging or young adulthood, the period between 18 and 25 years of age, is a distinct developmental phase with unique tasks and expectations. It is characterized by pervasive changes in autonomy, residence, identity, social roles, and career pursuits . Successfully negotiating the transitions of young adulthood is associated with positive trajectories of mental health well being and allows for optimal development during adulthood . Emerging adulthood is a period that involves extensive and often concurrent contextual and social role changes, increased self-direction and opportunities for exploration flexibility . In young adulthood,planting drying rack symptoms of depression and symptoms of anxiety are the most common mental health concerns . Mental health. Poor mental health in early adulthood has been shown to be a strong individual predictor of persistent and recurrent mental health problems into adulthood . Mental health processes during these critical transitional years can however be positively influenced, given opportunities to do so .

Differently said, there are as many opportunities to disrupt and negatively influence mental health and the transition from young adulthood to adulthood as there are opportunities to positively impact mental health and promote a successful transition from young adulthood to adulthood. Depression1 . As one of the most common health disorders in the United States , depression is a leading cause of disability, diminished quality of life and heightened risk for physical health problems . Depression is a serious psychopathological disorder that can have a consequential economic drain on individuals, families, society, lead to long-term suffering, risk of suicide, occupational impairment, and interpersonal impairment in peer and family relationships . Depressive disorders are characterized “by pervasive mood disturbances that involve feelings of sadness and loss of interest or pleasure in most activities in conjunction with disturbances in sleep, appetite, concentration, libido and energy” . The chronicity of the disorder can remain burdensome for a significant period . Individuals between the ages of 15 and 24 experience the highest rates of depressive disorders in the United States . The incidence of depression increases in adolescence and peaks in young adulthood . Prevalence estimates place the rate for Major Depressive Disorders in young adults at 15.4% . Between 2013 and 2015, the 12-month prevalence of a Major Depressive Episode, a period characterized by low mood and depression symptoms, among young adults ages 18 to 25 rose from 8.7% to 10.3% . Furthermore, rates of Major Depressive Episodes are almost double for females compared to males ages 18 and over .Depressed mood, one of our outcomes of interest, is defined as a single symptom or group of symptoms that involve a dysphoric effect . Between 2013 and 2015, approximately 5% of the 18-24 age group reported experiencing two or more symptoms of depression in the past 30 days . Anxiety. Anxiety disorders are often comorbid with depression and substance use disorders, and are associated with fear, nervousness, apprehension, and panic, but may also involve the cardiovascular, respiratory, gastro or nervous system, individually or in combination . Anxiety disorders are subdivided into panic disorder, social phobia, posttraumatic stress disorders, obsessive compulsive disorders, and generalized anxiety disorders .

They tend to start early in life, and affect school and work performance as well as psychological functioning, and social relationships, and are persistent and chronic . Anxiety disorders are a leading cause of disability among all psychiatric disorders . Anxiety can be as disabling as chronic somatic disorders, and is associated with reduced productivity, absenteeism from school or work, suicide, increased likelihood of school dropout, marital instability, and poor career choices , all of which are crucial to successfully transition from young adulthood to adulthood. Young adulthood is a period of heightened risk for the onset of anxiety disorders . Past year rates of anxiety amongst 18 to 29-year-old were elevated at 30.2% in 2005 . Rates of anxiety amongst young adults are as worrisome with the lifetime prevalence of any anxiety disorder in the 18 to 29 age bracket being 30.2% in 2005 , compared to a lifetime prevalence of 28.8% in the total United States population . Furthermore, past year prevalence of any anxiety disorder was higher for females than for males . In addition to being a period marked by mental health vulnerabilities , young adulthood is also a period marked by increased drug use. Mental health vulnerabilities, such as those present in young adulthood, can be exacerbated by drug use, thus potentially hindering or delaying a successful transition to adulthood. Traditional risk factors associated with onset of marijuana use in adolescence and maintenance of use in young adulthood are being male, prior or concurrent alcohol and tobacco use, poor parental relationships, and peers who use marijuana . Marijuana use is associated with poor academic achievement, lower expectations for success, family problems, and other drug use . Marijuana use is also common among young adults and is on the rise. Rates of marijuana use by adults ages 18 to 29 have steadily risen from 10.5 percent to 21.1 percent since 2005 and 19.8 percent of 18 to 25-year-old report using marijuana in the past month . Furthermore, between 1990 and 2002, rates of marijuana disorders increased from 25% to 32% amongst 18 to 29 year olds . There are gender differences in rates of marijuana use by young adults with 23.4% of males ages 18-25 reporting past month use of marijuana, and 16.2% of females of the same age group reporting past month use. Past year use was 36.0% for males and 28.4% for females ages 18-25 in 2015 .

These prevalence rates suggest that marijuana use varies across gender and that there may be inherent differences in patterns of use and associated outcomes across groups. Thus far, research that has sought to disentangle the association between marijuana use and associated outcomes has largely been conducted in a context where marijuana use is illegal. As more states move forward with either the legalization of recreational or medical marijuana use, it is important to understand what the associations between motives of marijuana use and associated outcomes might be in such a context. Prior work has demonstrated key differences between states that have moved toward legalization compared to those who have not. For instance,hydroponic rack populations in states that have moved forward with legalization had higher rates of marijuana use to begin with and perceived marijuana use as not risky . Marijuana use has also been found to be higher in states that allow medical use . In these states, past month marijuana use as well as heavy marijuana use were higher than in states without legalized medical marijuana . Legalization of medical marijuana has also been associated with increases in reported marijuana use. Using Los Angeles County as an example, past year rates of marijuana use have increased for both men and women and across all racial and ethnic groups between 2005 and 2015 . Among those who reported marijuana use in Los Angeles County, adults between the ages of 18 and 29 are those that reported the highest rates of use compared to other age groups . Other work by Pacula et al. has demonstrated a significant overlap between medical and recreational use, even in states where recreational use was not legal. In a different study, with regards to reasons of use, 89.5% of adults who report marijuana use report doing so mainly for recreational purposes, 10.5% uniquely for medical purposes, and 36.1% reported a mixed use . In sum, it appears as though legalizing marijuana, whether only medical or both medical and recreational, has brought forth changes not only in the prevalence of use but also contributes to validating the perception of marijuana as a safe drug to use. Furthermore, for some individuals who use marijuana, there does not seem to be a clear divide between medical use and recreational use. There are three hypothesized ways in which marijuana and mental health are thought to be associated, and these may not be mutually exclusive. First, through a common risk factor such as family or individual characteristics .This suggests that the relationship between marijuana use and mental health is non-causal, and explained by overlapping psychosocial risk factors . Second, via early self-medication and subsequent association with a subculture that uses drugs . Here, early use to alleviate symptoms encourages later use which can have an impact on anticonventional behaviors, increase of delinquency, and personal difficulties . Third, marijuana use can bring about its own consequences by worsening mental health through direct effects on psychological and physiological functioning or related effects on interpersonal and role functioning .

This third point is reinforced by work that demonstrates clear and consistent associations and dose-response relations between the frequency of adolescent marijuana use and all adverse young adult outcomes, which included decreased odds of high school completion, and degree attainment, increased odds of marijuana use disorder or alcohol and other use disorders, and suicide attempts . Although there is increasing recognition that marijuana use could be associated to affect based psychological susceptibility , the evidence is inconclusive. Use of marijuana among young people has been inconsistently associated with co-morbid or concurrent mental health problems in cross sectional and longitudinal studies . Some studies have demonstrated that frequent marijuana use is associated with higher levels of anxiety . Other studies, have demonstrated that marijuana may not play a causal role in the development of anxiety , or that the associations between marijuana use and mental health outcomes disappear after adjusting for confounders . The directionality of the association between marijuana use and mental health outcomes also remains unclear. Although the anxiolytic effects of marijuana have been supported in cross sectional studies , longitudinal studies have demonstrated that frequent marijuana use preceded anxiety disorders , while in others anxiety disorders preceded use . Other longitudinal studies have also demonstrated no associations between marijuana and anxiety disorders . This illustrates the importance of choice and inclusion of confounders and intervening variables in the study of marijuana use and mental health. Depressive and anxious disorders are more common in women compare to men whereas substance use disorders are more common in men than women . Two possible explanations for these trends are gender socialization and the operationalization of mental health symptoms. Gender socialization is the process whereby both men and women learn of and conform to gender specific traits . Illustrative of that are previously demonstrated gender differences in responses to stressors whereas men are more likely to externalize distress and turn to substance use and women are more likely to internalize stress and exhibit more symptoms of depression and anxiety . Instruments used to operationalize mental health and symptoms of mental health rely heavily on women gendered symptoms. As a result, men may under report or misreport their mental health distress or status because the indicators or symptoms assessed are not reflective of their experiences. Work by Martin et al. has demonstrated that men who are depressed are more likely to endorse symptoms such as anger, self-destructive behavior, risk taking, and substance use over the more, traditionally women endorsed, symptoms of sadness, loss of interest, and hopelessness. In fact, in the same study by Martin et al. , there were no differences in prevalence rates between men and women when symptoms of depression were assessed using a scale that combined both men and women specific symptoms.